The present invention relates generally to a packet processing device, and more particularly to an IP packet processing device constructed of a multi-engine type or multi-task type packet processing engine module, and a search engine.
Over the recent years, there has been a sharp increase in use of an IP network in a form of being applied to the Internet and an intranet (enterprise network), wherein an IP (Internet Protocol) protocol is utilized as a network layer protocol. What is demanded with this increase is an enhancement of performance of the IP packet processing device such as a router for executing a routing process of an IP packet (which might simply be termed a packet unless specified otherwise) in the IP network.
Further, with an introduction and an extension of the IP network, mainly an IP traffic occupies data communications. An IP packet is, however, defined as variable-length IP datagram, and a problem is therefore how a quality of service (QoS) is guaranteed with respect to a deficiency of throughput for a burst traffic of short packets, an influence upon other packets when reading long packets and so on.
Generally, the IP packet processing device includes a packet processing engine module for executing a packet process and a search engine module for executing a search process in a packet routing process. In this IP packet processing device, when executing the routing process of the packet, the search process is implemented based on a destination address contained in a header field of the inputted packet, and a destination (a MAC address etc) is determined from information obtained, thereby forwarding the packet.
As elements differentiating a product, additions of various categories of service functions and an increase in accommodation factor for a product cost, are further demanded of the IP packet processing device in a network-sided system. Moreover, for responding to a request for further improving the packet routing throughput, a scheme is becoming a mainstream that the packet processing engine module takes an architecture in which network processors (NPs) having a plurality of built-in engines (multi engines) execute a distributed process at a high speed, and that the search engine module uses a large-capacity CAM (Content Addressable Memory) capable of processing a multi-bits high-speed search.
The additions of the new functions required of the IP packet processing device show an increasing trend, and a throughput of the packet processing is as high as 2.4 Gbps or 10 Gbps, wherein a throughput even a high-speed operating network processor can not reach those levels.
Further, the search process required of the search engine module is increasingly diversified into a routing (route information) search, a filtering search, a classifying search and so forth, with the result that a search process time is not ignored even when using the high-speed CAM.